Medical cannabis provides marginal pain relief in advanced cancer
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Key takeaways:
- Patients who received medical cannabis had a small improvement in cancer-related pain.
- Pain relief provided by medical cannabis does not reach the level of providing a clinical benefit.
CHICAGO — Individuals with advanced cancer who received a two-component medical cannabis oil reported improvement in cancer-related pain, results from a randomized study showed.
However, according to data presented at ASCO Annual Meeting, the pain relief came in tandem with increased psychomimetic toxicity and despite being statistically significant, did not reach the level typically considered to be clinically beneficial. Moreover, the addition of medical cannabis did not provide clinical benefits to improve overall cancer-related symptoms compared with palliative care alone.
“Medicinal cannabis is very popular among patients with advanced cancer but there is very little quality evidence to support its use in symptom control,” Janet Rea Hardy, MD, of the University of Queensland, said during a presentation.
“This trial measured total symptom burden over time, rather than individual symptoms, and failed to show that medicinal cannabis improved the overall benefit that can be delivered by palliative care,” she added. “It remains difficult to define a place for medicinal cannabis in symptom control.”
Background and methodology
Previous research by Hardy and colleagues published in Journal of Clinical Oncology showed that cannabidiol (CBD) oil did not improve symptom management above that already provided through palliative care.
The investigators have subsequently conducted a study of the same design to investigate whether the addition of tetrahydrocannabinol (THC) oil to CBD would improve symptoms. Inclusion criteria required participants to have a total symptom distress score of at least 10 out of 90, as measured by the Edmonton Symptom Assessment Scale.
Researchers randomly assigned 144 patients with advanced cancer undergoing palliative care to receive combination 10 mg/mL THC:10 mg/mL CBD oil or placebo. The most common forms of cancer among patients in the study included breast, lung and gynecologic cancers.
Study participants had their dose increased according to tolerance and perceived efficacy from 2.5 to 30 mg/day over a 14-day period and continued until day 28.
Change in total symptom distress score from baseline to day 14 served as the study’s primary outcome measurement, with secondary outcomes that included change in individual symptoms, patient-selected dose, anxiety or depression, opioid use, quality of life and toxicity.
Results, next steps
Participants in the investigative cohort had a mean baseline total symptom distress score of 37.6 compared with 36.5 in the control group.
The mean baseline total symptom distress score dropped over time, with no observed difference between study arms at day 14 (6.3 ± 12.3 for medical cannabis and 6.98 ± 12.6 for placebo) or day 28 (9.24 ± 15.3 for medical cannabis and 8.42 ± 13.6 for placebo).
When adjusted for baseline, researchers noted a significant improvement in pain score favoring medicinal cannabis (1.41 ± 2.15 vs. 0.46 ± 2.82) and overall well-being favoring placebo (0.48 ± 2.78 vs. 1.29 ± 2.74) at day 14.
Additional findings showed a median patient-selected dose of oil at day 14 of 1.5 mL (range 0.5-3) and 3 mL (range 0.5-3) for placebo.
Study investigators reported adverse events related to medical cannabis intervention as “generally mild.”
Compared with baseline assessments, more participants who received medical cannabis reported confusion, feeling “high,” and an exaggerated sense of well-being.
Study limitations noted by the researchers included that most patients had been recruited at one site and the study not being powered for secondary outcomes.
Moving forward, researchers plan to further investigate potential uses for medical cannabis to better define its potential benefits for certain patients.
“We’ve been able to demonstrate the benefit that palliative care can deliver to [patients with advanced cancer] with symptoms; we’ve been unable to show that a combination THC/CBD oil leads to any significant benefit over palliative care and it comes at a cost of increased toxicity,” Hardy said. “An ongoing research program is trying to define whether there is any other combination of cannabinoids that would be of any benefit or if there are any symptoms most likely to benefit while also looking at assessment tools.”
References:
- Hardy JR, et al. Abstract 12020. Presented at: ASCO Annual Meeting; May 30–June 4, 2024; Chicago.
- Hardy J, et al. J Clin Oncol. 2023;doi:10.1200/JCO.22.01632.
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Hardy JR, et al. Abstract 12020. Presented at: ASCO Annual Meeting; May 30–June 4, 2024; Chicago.
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